Busses are free here now too, but it's warm. The homeless would rather be outside. They have their hangouts and cliques just like the 'homed'. Are they really just riding around for warmth there? No shelter they can go to?
Have they blocked or removed any seats, put up a plastic shield for you or given you a mask? Those things are happening here.
As you said, you're (more than) probably going to be ok. You've already beaten death with experience.